This invention relates to folding apparatus and, more particularly, for apparatus useful in the production of a quarter-folded product such as a paper napkin.
Napkin folders have been available for a long time. The procedure employed over the years is straight-forward and well known, i.e., a web is longitudinally folded by passing through a plow or similar V-plate after which the two-ply web is transversely cut into discrete lengths. Thereafter, the web is passed through a series of rollers that sequentially cut the web into discrete segments. Normally, to get a square unfolded napkin, the cutoff distance is twice the width of the longitudinally folded web. Thereafter, through the use of a vacuum roll, an intermediate portion of the now discrete web segment is gripped and caused to fold on itself transversely--thereby developing a napkin one-quarter the area of the unfolded web.
This general arrangement is depicted in a number of subsequent, co-owned patents. For example, U.S. Pat. Nos. 3,256,012 and 3,740,049 have to do with packing devices that deliver individual folded napkins into delivery magazines after they have been processed as above. U.S. Pat. Nos. 3,689,061 and 3,870,292 also show the same general procedure outlined above but proceed further in teaching the means for introducing additional folds.
Also over the years, the art workers have learned that it is most efficient to operate with a two-wide parent roll so as to produce two napkins simultaneously. Use of two-wide parent rolls, slitting and simultaneously processing of the separated and continuous web halves was, and remains, a space efficient and highly productive arrangement that doubles producing by using a duplicate series of rollers to produce pairs of superposed napkins which are subsequently stripped from vertical delivery belts by a reciprocating or orbiting packer finger for delivery into a magazine for manual packing. Numerous machines with vertical delivery systems of this type are in production worldwide, but in more competitive markets and with escalating labor costs, the addition of automatic stacking and automatic delivery of pre-counted stacks becomes all important for cost effective productivity.
The optimum arrangement of a two-wide parent folder would be to have the slit webs travel vertically downward into folding rolls and then horizontally away so as to be orbitally packed--it being appreciated that where the napkins delivered vertically (as they have for many years), they must stand on end, a difficult achievement for relatively flimsy webs. To perform the entire sequence horizontally is and has been, unacceptable because of space requirements.
The attempts to provide the optimum arrangement have suffered from crucial defects. One approach was to place a folding roll on each side of the horizontal delivery path. This meant an extensive or long "draw" of one of the slit portions of the parent web and caused the operation to be unreliable at times besides occupying extra space and raising the possibility of improper registry of embossing patterns. The alternative would be to place the folding rolls side-by-side in horizontally aligned relation in the paths of the two slit webs from the parent roll to avoid unequal draws. But this posed a deterrent because to deliver the quarter-folded napkins along a horizontal path, the webs would have to be distorted while their direction of travel was changed.
According to the present invention, the optimum arrangement has been achieved through the use of special belt means which operate to strip the product from one folding roll and thereafter urge the product against a simultaneously produced product carried by the other roll and which also delivers both products in superposed relation along the advantageous horizontal path.
Other objects and details of the invention may be seen in the details of the ensuing specification.